CN112653532B - Clock synchronization method, device and system - Google Patents
Clock synchronization method, device and system Download PDFInfo
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Abstract
The invention discloses a method, a device and a system for clock synchronization. Wherein, the method comprises the following steps: determining a type of a video output node, wherein the type comprises: a master node and a slave node; performing clock synchronization on the slave node and the master node according to a preset protocol; and correcting the clock signals output by the master node and the slave node after the clock synchronization through the timer. The invention solves the technical problem that the clock synchronization of all nodes cannot be ensured by a plurality of output nodes because the prior art relies on an external clock to carry out display synchronization when ensuring the output display synchronization.
Description
Technical Field
The invention relates to the technical field of display, in particular to a method, a device and a system for clock synchronization.
Background
Along with the continuous progress of the technology, the functions of equipment are more and more, the resolution ratio of display is higher and higher, and the size of an LED display screen is larger and larger, so that the requirement of large-screen display of an LED cannot be met by one-way output, multiple paths of output are often needed to be spliced or multiple pieces of equipment are needed to be spliced to finish the display of the LED, and therefore how to synchronize the multiple output displays becomes a hot problem in the field.
In a related technology that can be realized, the external genlock synchronization, the node external genlock source, the Field Programmable Gate Array (FPGA) display uses the external genlock source as the synchronization source, each output node uses the clock of the genlock source, thereby ensuring the output display synchronization. But it needs to rely on an external genlock source, and when there are multiple output nodes, it is difficult to ensure that the genlock signal clocks and phases of all nodes are synchronous.
In another related technique that may be implemented, input source synchronization, similar to genlock synchronization, uses the input source as the synchronization source and the input source clock as the synchronization clock, the principle being consistent with genlock synchronization. However, an external input source is required in the equipment, and when no input source exists in the specification of the equipment, the scheme cannot be used.
In view of the above-mentioned problem that in the prior art, the clock synchronization of all the nodes cannot be ensured by a plurality of output nodes because the display synchronization is performed by depending on an external clock when the output display synchronization is ensured, an effective solution is not proposed at present.
Disclosure of Invention
The embodiment of the invention provides a clock synchronization method, a clock synchronization device and a clock synchronization system, which are used for at least solving the technical problem that clock synchronization of all nodes cannot be ensured by a plurality of output nodes because the prior art relies on an external clock to perform display synchronization when output display synchronization is ensured.
According to an aspect of an embodiment of the present invention, there is provided a clock synchronization method, including: determining a type of a video output node, wherein the type comprises: a master node and a slave node; performing clock synchronization on the slave node and the master node according to a preset protocol; and correcting the clock signals output by the master node and the slave node after the clock synchronization through the timer.
Optionally, the performing clock synchronization on the slave node and the master node according to the preset protocol includes: according to the clock of the main node, the time synchronization and the time information are issued periodically, wherein the time information comprises: timestamp information; receiving timestamp information sent by a clock port of a master node through a clock port of a slave node; and calculating the time difference between the master node and the slave node according to the timestamp information, and adjusting the local time of the timer according to the time difference to obtain the clock frequency and phase consistency of the master node and the slave node.
Optionally, the modifying, by the timer, the clock signals output by the master node and the slave node after the clock synchronization includes: setting the timing duration of a timer according to the frame rate of a video source input into a video output node to obtain the set timer; and carrying out phase synchronization on the clock signals of the master node and the slave node according to the set timer to obtain a corrected clock signal.
Further, optionally, performing phase synchronization on the clock signals of the master node and the slave node according to the set timer to obtain the corrected clock signal includes: and controlling the set timers of the master node and the slave node to start at the starting point of the designated time, and synchronously outputting the clock signals of the master node and the slave node to obtain a corrected clock signal.
Optionally, performing phase synchronization on clock signals of the master node and the slave node according to the set timer, and obtaining a corrected clock signal includes: and sending a multicast instruction to the slave nodes by the master node, wherein the multicast instruction is used for indicating the start of timers of all the nodes, and synchronously outputting clock signals of the master node and the slave nodes to obtain a corrected clock signal.
According to another aspect of the embodiments of the present invention, there is also provided a clock synchronization apparatus, including: the type determining module is used for determining the type of the video output node, wherein the type comprises the following components: a master node and a slave node; the synchronization module is used for carrying out clock synchronization on the slave node and the master node according to a preset protocol; and the correction module is used for correcting the clock signals output by the master node and the slave node after the clock synchronization through the timer.
Further, optionally, the modification module includes: the setting unit is used for setting a timer according to the frame rate of a video source of the input video output node to obtain the set timer; and the correcting unit is used for carrying out phase synchronization on the clock signals of the main node and the slave node according to the set timer to obtain a corrected clock signal.
Optionally, the correction unit includes: and the first correction subunit is used for controlling the set timers of the master node and the slave node to start at the starting point of the specified time, and synchronously outputting the clock signals of the master node and the slave node to obtain the corrected clock signals.
Optionally, the correction unit includes: and the second correction subunit is used for sending a multicast instruction to the slave node through the master node, wherein the multicast instruction is used for indicating the start of the timers of all the nodes and synchronously outputting the clock signals of the master node and the slave node to obtain a corrected clock signal.
According to another aspect of the embodiments of the present invention, there is also provided a system for clock synchronization, including: switch and display device, clock synchronization system still includes: the system comprises at least two multimedia playing boxes, a switch, a display device and a switch, wherein the switch is respectively connected with the at least two multimedia playing boxes, each multimedia playing box is connected with the corresponding display device, and the number of the display devices is the same as that of the multimedia playing boxes; determining the types of at least two multimedia playing boxes, wherein the types comprise: a master node and a slave node; performing clock synchronization on the slave node and the master node according to a preset protocol; and correcting the clock signals output by the master node and the slave node after clock synchronization through a timer.
Optionally, each multimedia play box includes: the system comprises a first-class data processing module and a field programmable gate array module, wherein one end of the first-class data processing module is connected with a switch, the other end of the first-class data processing module is connected with one end of the field programmable gate array module and used for storing and executing a system program, acquiring a frame rate in multimedia data output by the switch, setting the timing duration of a timer according to the frame rate, and controlling the synchronization of clock signals output between each multimedia playing box according to the set timer; the other end of the field programmable gate array module is connected with the display device and used for outputting the multimedia data synchronized with the clock signal to the display device.
Optionally, each multimedia playing box includes: the system comprises a first-class data processing module, a second-class data processing module and a field programmable gate array module, wherein one end of the first-class data processing module is connected with a switch, the other end of the first-class data processing module is connected with one end of the second-class data processing module, and the second-class data processing module is connected with one end of the field programmable gate array module; the first type data processing module is used for storing and executing system programs; acquiring a frame rate in multimedia data output by the switch according to the service request, setting the timing duration of the timer according to the frame rate, and controlling the synchronization of clock signals output between each multimedia playing box according to the set timer; or, the service request is sent to a second type data processing module, the second type data processing module sets a timer according to the frame rate in the multimedia data output by the switch, and controls the clock signal output between each multimedia playing box to be synchronous according to the set timer; the other end of the field programmable gate array module is connected with the display device and used for outputting the multimedia data synchronized with the clock signal to the display device.
According to another aspect of the embodiments of the present invention, there is also provided a storage medium, where the storage medium includes a stored program, and where the apparatus on which the storage medium is located is controlled to execute the above method when the program runs.
According to another aspect of the embodiments of the present invention, there is also provided a processor, where the processor is configured to execute a program, where the program executes the method described above.
In the embodiment of the invention, the type of a video output node is determined by adopting a clock synchronization mode of a distributed system, wherein the type comprises the following steps: a master node and a slave node; performing clock synchronization on the slave node and the master node according to a preset protocol; clock signals output by a master node and slave nodes after clock synchronization are corrected through a timer, the aim of video synchronization when a plurality of output nodes are spliced in a distributed system without depending on an external clock is achieved, the technical effect of clock synchronization when the plurality of output nodes are spliced in the distributed system is achieved, and the technical problem that in the prior art, the clock synchronization of all the nodes cannot be ensured due to the fact that the plurality of output nodes display and synchronize by depending on the external clock when the output display synchronization is ensured is solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention and do not constitute a limitation of the invention. In the drawings:
FIG. 1 is a flow diagram of a method of clock synchronization according to an embodiment of the invention;
FIGS. 2a and 2b are schematic diagrams of an architecture in a method of clock synchronization according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of an apparatus for clock synchronization according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a system for clock synchronization according to an embodiment of the present invention;
FIG. 5a is a schematic diagram of a system for clock synchronization according to an embodiment of the present invention;
fig. 5b is a schematic diagram of another system for clock synchronization according to an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Moreover, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example 1
In accordance with an embodiment of the present invention, there is provided a method embodiment of a method of clock synchronization, it being noted that the steps illustrated in the flowchart of the figure may be performed in a computer system such as a set of computer-executable instructions and that, although a logical order is illustrated in the flowchart, in some cases the steps illustrated or described may be performed in an order different than that presented herein.
Fig. 1 is a schematic flow chart of a method for clock synchronization according to an embodiment of the present invention, as shown in fig. 1, the method includes the following steps:
step S102, determining the type of a video output node, wherein the type comprises: a master node and a slave node;
specifically, the clock synchronization method provided in the embodiment of the present application may be applicable to a distributed system, and particularly may be applied to a video splicing display scenario, where there are at least two video output nodes in the embodiment of the present application, the number of the video output nodes is determined according to the needs of a display service, for example, a 4 × 4 display structure, 6 × 6,8 × 8, etc., each video output node corresponds to one output to an LED large-screen display, and the resolution requirement of 1080p,2k,4k is obtained by splicing through multiple outputs.
In the embodiment of the present application, because the present application is applied to a distributed system, a plurality of video output nodes may obtain a master node and a plurality of slave nodes according to a determined type, in an implementable manner, fig. 2a and 2b are schematic diagrams of an architecture in a clock synchronization method according to an embodiment of the present invention, and as shown in fig. 2a and 2b, a description is given by taking clock synchronization of three video output nodes as an example:
and determining to obtain a main node and two slave nodes by the three video output nodes according to software designation.
Step S104, performing clock synchronization on the slave node and the master node according to a preset protocol;
specifically, based on the master node and the slave node obtained in step S102, with reference to fig. 2a and 2b, the slave node performs clock synchronization with the master node according to a preset protocol, where the preset protocol in this embodiment is described by taking a 1588 protocol as an example, that is, in step S104, the slave node performs clock synchronization with the master node through the 1588 protocol.
Optionally, the performing clock synchronization on the slave node and the master node according to the preset protocol includes: according to the clock of the master node, the time synchronization and the time information are issued periodically, wherein the time information comprises: timestamp information; receiving timestamp information sent by a clock port of a master node through a clock port of a slave node; and calculating the line time delay between the master node and the slave node and the time difference between the master node and the slave node according to the timestamp information, and adjusting the local time of the timer according to the time difference to obtain the clock frequency and the phase of the master node and the clock frequency of the slave node to be consistent.
Specifically, in the embodiment of the present application, a 1588 protocol is taken as an example for description, where 1588 is a master-slave synchronization system. In the synchronization process of the system, a master clock periodically issues PTP time synchronization and time information, a slave clock port receives timestamp information sent by the master clock port, the system calculates master-slave line time delay and master-slave time difference according to the information, and local time is adjusted by using the time difference, so that the equipment time is kept at the frequency and the phase consistent with the master equipment time. 1588 frequency synchronization and phase synchronization can be achieved simultaneously.
The following explains the processing procedure of 1588 for realizing time synchronization:
(assuming that the delay from Master to Slave is the same as the delay from Slave to Master.)
1. The Master node (Master) sends a synchronization message to the Slave node (Slave) and registers the transmission time T1.
2. The Slave node (Slave) receives the "synchronization" message and records the time T2 received.
3. The Master node (Master) sends a Follow (Follow _ Up) message to the Slave node (Slave), and embeds the time T1 into the Follow message.
4. The slave node sends a Delay request (Delay _ Req) message to the master node and embeds a timestamp T3.
5. The master node receives the "delay request" message and remembers time T4.
6. The master node embeds T4 into a Delay response (Delay _ Resp) message and sends the message to the slave node.
From these four times, the Delay (Delay) and time Offset (Offset) between the Slave and the Master can be calculated:
average path delay:
1. the Master node (Master) sends a synchronization message to the Slave node (Slave) and registers the transmission time T1.
2. The Slave node (Slave) receives the 'synchronization' message and records the received time T2.
3. The Master node (Master) sends a Follow (Follow _ Up) message to the Slave node (Slave), and embeds the time T1 into the Follow message.
4. The slave node sends a Delay request (Delay _ Req) message to the master node and embeds a timestamp T3.
5. The master node receives the "delay request" message and remembers time T4.
6. The master node embeds T4 into a Delay response (Delay _ Resp) message and sends the message to the slave node.
From these four times, the Delay (Delay) and time Offset (Offset) between the Slave and the Master can be calculated:
and the Slave end clock can be corrected according to the Offset to realize synchronization.
And step S106, correcting the clock signals output by the master node and the slave node after the clock synchronization through the timer.
Specifically, based on the clock synchronization between the slave node and the master node in step S104, in order to improve the precision of the video synchronized playback output by the multiple nodes, the clock output by each node needs to be further modified, so as to modify the clock generated by the high and low levels of the input/output IO specified by each node.
The difference between fig. 2a and fig. 2b is that one of the timers used is the advanced Linux timer shown in fig. 2a, and the other is the advanced MCU timer shown in fig. 2 b. The advanced MCU timer is positioned in the MCU processor and based on the characteristic that the MCU processor can process real-time data, a more accurate clock signal can be obtained through the advanced MCU timer in the embodiment of the application.
Optionally, the step S106 of correcting, by the timer, the clock signals output by the master node and the slave node after the clock synchronization includes:
step S1061, setting the timing duration of a timer according to the frame rate of a video source of an input video output node to obtain the set timer;
specifically, what is to be presented finally in the embodiment of the present application is that the video sources output by the multiple nodes are displayed synchronously on the LED screen by splicing, so how to ensure synchronous display needs to set the timing duration of the timer according to the frame rate of the video sources. It should be noted that, in the embodiment of the present application, to synchronously display the video sources output by multiple nodes in one LED screen, the frame rates of the video sources output by each node are set to be the same.
Step S1062, performing phase synchronization on the clock signals of the master node and the slave node according to the set timer, to obtain a corrected clock signal.
Based on the timer set according to the frame rate in step S1061, the output of the video source is triggered by the set timer, so as to modify the clock generated by the high and low levels of the designated input/output port IO.
Specifically, it should be noted that phase synchronization is required for generating clocks, that is, all rising edges and falling edges of the clocks correspond to each other, so that the embodiment of the present application includes two ways in implementing step S1062:
the first method is as follows: and controlling the set timers of the master node and the slave node to start at the starting point of the designated time, and synchronously outputting the clock signals of the master node and the slave node to obtain a corrected clock signal.
Specifically, all timers are controlled to start the timers at the starting point of 1s, wherein a precondition for realizing the first mode is that: it is ensured that the generated clock corresponds to an integer frame rate, so that at the beginning of each second, the level conversion is consistent every second.
The second method comprises the following steps: and sending a multicast instruction to the slave nodes by the master node, wherein the multicast instruction is used for indicating the start of timers of all the nodes, and synchronously outputting clock signals of the master node and the slave nodes to obtain a corrected clock signal.
Specifically, after the locking is successful, the master node sends out a multicast command to inform all nodes of starting, wherein the precondition for implementing the second mode is that: all nodes need to be guaranteed to receive the starting instruction at the same time, so that the requirement on the network environment is high.
In the embodiment of the invention, the type of a video output node is determined by adopting a clock synchronization mode of a distributed system, wherein the type comprises the following steps: a master node and a slave node; performing clock synchronization on the slave node and the master node according to a preset protocol; clock signals output by a master node and slave nodes after clock synchronization are corrected through a timer, the aim of video synchronization when a plurality of output nodes are spliced in a distributed system without depending on an external clock is achieved, the technical effect of clock synchronization when the plurality of output nodes are spliced in the distributed system is achieved, and the technical problem that in the prior art, the clock synchronization of all the nodes cannot be ensured due to the fact that the plurality of output nodes display and synchronize by depending on the external clock when the output display synchronization is ensured is solved.
Example 2
According to another aspect of the embodiments of the present invention, there is also provided a clock synchronization apparatus, and fig. 3 is a schematic diagram of the clock synchronization apparatus according to the embodiments of the present invention, as shown in fig. 3, including: a type determining module 32, configured to determine a type of the video output node, where the type includes: a master node and a slave node; a synchronization module 34, configured to perform clock synchronization on the slave node and the master node according to a preset protocol; and a correcting module 36, configured to correct, by using the timer, the clock signals output by the master node and the slave node after clock synchronization.
Optionally, the synchronization module 34 includes: a sending unit, configured to periodically issue time synchronization and time information according to a clock of a master node, where the time information includes: timestamp information; the receiving unit is used for receiving the timestamp information sent by the clock port of the master node through the clock port of the slave node; and the synchronization unit is used for calculating the time difference between the master node and the slave node according to the time stamp information, and adjusting the local time of the timer according to the time difference to obtain the clock frequency and phase consistency of the master node and the slave node.
Further, optionally, the modification module 36 includes: the setting unit is used for setting the timing duration of the timer according to the frame rate of the video source of the input video output node to obtain the set timer; and the correcting unit is used for carrying out phase synchronization on the clock signals of the master node and the slave node according to the set timer to obtain a corrected clock signal.
Optionally, the correction unit includes: and the first correction subunit is used for controlling the set timers of the master node and the slave node to start at the starting point of the specified time, and synchronously outputting the clock signals of the master node and the slave node to obtain the corrected clock signals.
Optionally, the correction unit includes: and the second correction subunit is used for sending a multicast instruction to the slave node through the master node, wherein the multicast instruction is used for indicating the start of the timers of all the nodes and synchronously outputting the clock signals of the master node and the slave node to obtain a corrected clock signal.
Example 3
According to another aspect of the embodiments of the present invention, there is also provided a system for clock synchronization, and fig. 4 is a schematic diagram of the system for clock synchronization according to the embodiments of the present invention, as shown in fig. 4, including: switch 42 and display device 44, the clock synchronization system provided by the embodiment of the present application further includes: at least two multimedia playing boxes 46, wherein the switch 42 is respectively connected with the at least two multimedia playing boxes 46, each multimedia playing box 46 is connected with a corresponding display device 44, and the number of the display devices 44 is the same as that of the multimedia playing boxes 46; determining the types of at least two multimedia play boxes 46, the types including: a master node and a slave node; performing clock synchronization on the slave node and the master node according to a preset protocol; and correcting the clock signals output by the master node and the slave node after clock synchronization through a timer.
Specifically, in the system for clock synchronization provided in the embodiment of the present application, the structure of the multimedia playing box includes the following two ways:
the first method is as follows: each multimedia play box 46 includes: the system comprises a first-class data processing module and a field programmable gate array module, wherein one end of the first-class data processing module is connected with a switch, the other end of the first-class data processing module is connected with one end of the field programmable gate array module and used for storing and executing a system program, acquiring a frame rate in multimedia data output by the switch, setting the timing duration of a timer according to the frame rate, and controlling the synchronization of clock signals output between each multimedia playing box according to the set timer; the other end of the field programmable gate array module is connected with the display device and is used for outputting the multimedia data synchronized with the clock signal to the display device.
Specifically, the first type data processing module may include: an ARM processor (Advanced RISC Machines, ARM for short), wherein the ARM processor comprises: the Linux advanced timer can perform a system-level data processing function due to the Linux-based architecture while providing a timer function, in an embodiment of the present invention, a clock signal (vsync) is generated by the Linux advanced timer, a field programmable gate array module is represented as an FPGA, fig. 5a is a schematic diagram of a clock synchronization system according to an embodiment of the present invention, as shown in fig. 5a, all ARM devices are connected to the same switch through a PHY (Port Physical Layer), an output node includes an ARM + FPGA (i.e., each node includes an ARM and an FPGA, where the FPGA is connected to the ARM and a display device, respectively), and the FPGA completes output. It should be noted here that the PHY on ARM must be a PHY supporting 1588 protocol.
The second method comprises the following steps: each multimedia play box 46 includes: the system comprises a first-class data processing module, a second-class data processing module and a field programmable gate array module, wherein one end of the first-class data processing module is connected with a switch, the other end of the first-class data processing module is connected with one end of the second-class data processing module, and the second-class data processing module is connected with one end of the field programmable gate array module; the first type data processing module is used for storing and executing system programs; acquiring a frame rate in multimedia data output by the switch according to the service request, setting the timing duration of the timer according to the frame rate, and controlling the synchronization of clock signals output between each multimedia playing box according to the set timer; or, the service request is sent to a second type data processing module, the second type data processing module sets a timer according to the frame rate in the multimedia data output by the switch, and controls the clock signal output between each multimedia playing box to be synchronous according to the set timer; the other end of the field programmable gate array module is connected with the display device and is used for outputting the multimedia data synchronized with the clock signal to the display device.
Specifically, the first type of data processing module may include: the ARM processor, the second class data processing module can include: an MCU processor (MCU Unit, abbreviated as MCU), a field programmable gate array module is denoted as FPGA, fig. 5b is a schematic diagram of another clock synchronization system according to an embodiment of the present invention, where, as shown in fig. 5b, all ARM devices are connected to the same switch through a PHY (Port Physical Layer), and an output node includes ARM + MCU + FPGA (i.e., each node includes ARM, MCU, and FPGA, where the FPGA is connected to the MCU and the display device, respectively), and the output is completed by the FPGA. It should be noted here that the PHY on ARM must be a PHY supporting 1588 protocol.
Example 4
According to another aspect of the embodiments of the present invention, there is also provided a storage medium, where the storage medium includes a stored program, and where when the program runs, a device in which the storage medium is located is controlled to execute the method in embodiment 1.
Example 5
According to another aspect of the embodiments of the present invention, there is also provided a processor, where the processor is configured to execute a program, where the program executes the method in embodiment 1.
The above-mentioned serial numbers of the embodiments of the present invention are only for description, and do not represent the advantages and disadvantages of the embodiments.
In the above embodiments of the present invention, the description of each embodiment has its own emphasis, and reference may be made to the related description of other embodiments for parts that are not described in detail in a certain embodiment.
In the embodiments provided in the present application, it should be understood that the disclosed technical content can be implemented in other manners. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and amendments can be made without departing from the principle of the present invention, and these modifications and amendments should also be considered as the protection scope of the present invention.
Claims (8)
1. A method of clock synchronization, comprising:
determining a type of a video output node, wherein the type includes: a master node and a slave node;
performing clock synchronization on the slave node and the master node according to a preset protocol;
correcting the clock signals output by the master node and the slave node after the clock synchronization through a timer;
wherein the clock synchronization of the slave node and the master node according to a preset protocol comprises: according to the clock of the main node, periodically issuing time synchronization and time information, wherein the time information comprises: timestamp information; receiving the timestamp information sent by the clock port of the master node through the clock port of the slave node; calculating the time difference between the master node and the slave node according to the timestamp information, and adjusting the local time of a timer according to the time difference to obtain the clock frequency and the phase of the master node and the clock frequency of the slave node are consistent;
the correcting, by a timer, the clock signals output by the master node and the slave node after the clock synchronization includes: setting the timing duration of the timer according to the frame rate of a video source input into the video output node to obtain the set timer; and carrying out phase synchronization on the clock signals of the main node and the slave node according to the set timer to obtain a corrected clock signal.
2. The method of claim 1, wherein the phase synchronizing the clock signals of the master node and the slave node according to the set timer to obtain the modified clock signals comprises:
and controlling the set timers of the master node and the slave node to start at the starting point of the designated time, and synchronously outputting the clock signals of the master node and the slave node to obtain a corrected clock signal.
3. The method of claim 1, wherein the phase synchronizing the clock signals of the master node and the slave node according to the set timer to obtain the modified clock signals comprises:
and sending a multicast instruction to the slave nodes through the master node, wherein the multicast instruction is used for indicating the start of timers of all the nodes, and synchronously outputting clock signals of the master node and the slave nodes to obtain a corrected clock signal.
4. An apparatus for clock synchronization, comprising:
a type determination module, configured to determine a type of a video output node, where the type includes: a master node and a slave node;
the synchronization module is used for carrying out clock synchronization on the slave node and the master node according to a preset protocol; wherein the clock synchronization of the slave node and the master node according to a preset protocol comprises: according to the clock of the main node, periodically issuing time synchronization and time information, wherein the time information comprises: timestamp information; receiving the timestamp information sent by the clock port of the master node through the clock port of the slave node; calculating the time difference between the master node and the slave node according to the timestamp information, and adjusting the local time of a timer according to the time difference to obtain the clock frequency and the phase of the master node and the clock frequency of the slave node are consistent;
the correction module is used for correcting the clock signals output by the master node and the slave node after the clock synchronization through a timer; wherein, the correcting, by the timer, the clock signals output by the master node and the slave node after the clock synchronization includes: setting the timing duration of the timer according to the frame rate of a video source input into the video output node to obtain the set timer; and carrying out phase synchronization on the clock signals of the main node and the slave node according to the set timer to obtain a corrected clock signal.
5. A system for clock synchronization, comprising: switch and display device, characterized in that, clock synchronization system still includes: at least two multimedia playing boxes, wherein,
the switch is respectively connected with the at least two multimedia playing boxes, each multimedia playing box is connected with the corresponding display equipment, and the number of the display equipment is the same as that of the multimedia playing boxes;
determining types of the at least two multimedia playing boxes, wherein the types comprise: a master node and a slave node; performing clock synchronization on the slave node and the master node according to a preset protocol; correcting the clock signals output by the master node and the slave node after the clock synchronization through a timer;
wherein the clock synchronization of the slave node and the master node according to a preset protocol comprises: according to the clock of the main node, periodically issuing time synchronization and time information, wherein the time information comprises: timestamp information; receiving the timestamp information sent by the clock port of the master node through the clock port of the slave node; calculating the time difference between the master node and the slave node according to the timestamp information, and adjusting the local time of a timer according to the time difference to obtain the clock frequency and the phase of the master node and the clock frequency of the slave node are consistent;
the correcting, by a timer, the clock signals output by the master node and the slave node after the clock synchronization includes: setting the timing duration of the timer according to the frame rate in the multimedia data output by the switch to obtain the set timer; and carrying out phase synchronization on the clock signals of the main node and the slave node according to the set timer to obtain a corrected clock signal.
6. The system of claim 5, wherein each multimedia play box comprises: a first type of data processing module and a field programmable gate array module, wherein,
one end of the first type data processing module is connected with the switch, the other end of the first type data processing module is connected with one end of the field programmable gate array module and used for storing and executing a system program, acquiring a frame rate in multimedia data output by the switch, setting the timing duration of a timer according to the frame rate, and controlling the synchronization of clock signals output between each multimedia playing box according to the set timer;
and the other end of the field programmable gate array module is connected with the display equipment and is used for outputting multimedia data synchronized with clock signals to the display equipment.
7. The system of claim 5, wherein each multimedia play box comprises: a first kind of data processing module, a second kind of data processing module and a field programmable gate array module, wherein,
one end of the first type data processing module is connected with the switch, the other end of the first type data processing module is connected with one end of the second type data processing module, and the second type data processing module is connected with one end of the field programmable logic gate array module;
the first type data processing module is used for storing and executing system programs; acquiring a frame rate in multimedia data output by the switch according to a service request, setting the timing duration of a timer according to the frame rate, and controlling the synchronization of clock signals output between each multimedia playing box according to the set timer; or, the service request is sent to the second type data processing module, the second type data processing module sets a timer according to the frame rate in the multimedia data output by the switch, and controls the clock signal output between each multimedia playing box to be synchronous according to the set timer;
and the other end of the field programmable gate array module is connected with the display equipment and is used for outputting multimedia data synchronized with clock signals to the display equipment.
8. A processor, wherein the processor is configured to run a program, wherein the program when executed performs the method of claim 1.
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